Introduction : The CollapsiblePanelExtender Control is a flexible extender control which help we can be easily add Collapsible sections in a Web page. This extender control target any ASP.NET Panel control.The page developer define which control on page should be open or close control for the Panel or the Panel set automatic expand or colapse when mouse cursor move in or out of.

The Panel is also post-back aware on a client post back, it automatically remembers and restores client state.